After the glue on my headstock dried, I cut off the excess wood around the edges with a pullsaw and a shinto rasp, then I brought it down to the proper thickness with a router. This was sloppy as hell because the clamp holding the jig that I made to the table snapped and the router slipped pretty badly. So, I took it down with a planer which worked out perfectly.
Then I filed the edges smooth (ish) and went to work on the volute with a half round file and a power drill drum sander, drilled the truss rod access hole and rounded off the drop off from the neck to the headstock the same way.
There's still some work to do here but it appears to be coming along pretty well.